samedi 21 mai 2016

Image above: The Solar Impulse 2 airplane rose from the cool tarmac at Tulsa International Airport with André Borschberg in the cockpit.

André Borschberg will continue crossing the United States today, flying from Tulsa, Oklahoma to Dayton, Ohio. He will takeoff at 9:30 AM UTC, 11:30 AM CET, and 04:30 AM CDT on May 21st from Tulsa International Airport and will be landing 17 hours and 30 minutes later at Dayton International Airport.

André Borschberg departure from Dayton

SolarImpulse Team have prepared a lot of material so that you can fully immerse yourself in this flight! Here’s a sneak peek of what we have in store for you:

vendredi 20 mai 2016

Image above: “The way physics develops is often a lot less logical than the theories it leads to -- you cannot plan discoveries. Especially in theoretical physics.” Gian Giudice, Head of CERN’s Theory Department (Image: Sophia Bennett/ CERN).

Over the past decade physicists have explored new corners of our world, and in doing so have answered some of the biggest questions of the past century.

When researchers discovered the Higgs boson in 2012, it was a huge moment of achievement. It showed theorists had been right to look towards the Standard Model for answers about our Universe. But then the particle acted just like the theorist’s said it would, it obeyed every rule they predicted. If it had acted just slightly differently it would have raised many questions about the theory, and our universe. Instead, it raised few questions and gave no new clues about to where to look next.

In other words, the theorists had done too good a job.

"We are struggling to find clear indications that can point us in the right direction. Some people see in this state of crisis a source of frustration. I see a source of excitement because new ideas have always thrived in moments of crisis." - Gian Giudice, head of the Theory Department at CERN.

Before these discoveries, physicists were standing on the edge of a metaphorical flat Earth, suspecting it was round but not knowing for sure. Finding both the Higgs boson, and evidence of gravitational waves has brought scientists closer than ever to understanding two of the great theories of our time – the Standard Model and the theory of relativity.

Now the future of theoretical physics is at a critical point – they proved their own theories, so what is there to do now?

So what next?

"Taking unexplained data, trying to fit it to the ideas of the universe […] – that’s the spirit of theoretical physics" – Gian Giudice

In an earlier article in this series, we spoke about how experimental physicists and theoretical physicists must work together. Their symbiotic relationship – with theorists telling experimentalists where to look, and experimentalists asking theorists for explanations of unusual findings – is necessary, if we are to keep making discoveries.

Just four years ago, in 2012, physicists still held a genuine uncertainty about whether the lynchpin of the Standard Model, the Higgs boson existed at all. Now, there’s much less uncertainty.

“We are still in an uncertain period, previously we were uncertain as to how the Standard Model could be completed. Now we know it is pretty much complete so we can focus on the questions beyond it, dark matter, the future of the universe, the beginning of the universe, little things like that,” says John Ellis, a theoretical physicist from Kings College, London who began working at CERN since 1973.

Image above: Michelangelo Mangano moved to the US to work at Princeton just as String Theory was made popular. "After the first big explosion of interest, there’s always a period of slowing down, because all the easier stuff has been done. And you’re struggling with more complex issues," he explains. "This is something that today’s young theorists are finding as they struggle to make waves in fields like the Standard Model. Unexpected findings from the LHC could reignite their enthusiasm and help younger researchers to feel like they can have an impact." (Image: Maximillien Brice/CERN).

With the discovery of the Higgs, there’s been a shift in this relationship, with theoreticians not necessarily leading the way. Instead, experiments look for data to try and give more evidence to the already proposed theories, and if something new is thrown up theorists scramble to explain and make sense of it.

"It’s like when you go mushroom hunting," says Michelangelo Mangano, a theoretical physicist who works closely with experimental physicists. "You spend all your energy looking, and at the end of the day you may not find anything. Here it’s the same, there is a lots of wasted energy because it doesn’t lead to much, but by exploring all corners of the field occasionally you find a little gold nugget, a perfect mushroom."

At the end of last year, both the ATLAS and CMS experiments at CERN found their mushroom, an intriguing, albeit very small, bump in the data.

This little, unexpected bump could be the door to a whole host of new physics, because it could be a new particle. After the discovery of the Higgs most of the holes in the Standard Model had been sewn up, but many physicists were optimistic about finding new anomalies.

Image above: John Ellis' office. (Image: Maximillien Brice/ CERN).

"What happens in the future largely depends on what the LHC finds in its second run," Ellis explains. "So if it turns out that there’s no other new physics and we’re focusing on understanding the Higgs boson better, that’s a different possible future for physics than if LHC Run 2 finds a new particle we need to understand."

While the bump is too small for physicists to announce it conclusively, there’s been hundreds of papers published by theoretical physicists as they leap to say what it might be.

“Taking unexplained data, trying to fit it to your ideas about the universe, revising your ideas once you get more data, and on and on until you have unravelled the story of the universe – that’s the spirit of theoretical physics,” expresses Giudice.

Image above: John Ellis classifies himself as a 'scientific optimist', who is happy to pick up whatever tools are available to him to help solve the problems that he has thought up. 'By nature I’m an optimist so anything can happen, yes, we might not see anything beyond the Higgs boson, but lets just wait and see.' Here he is interviewed by Harriet Jarlett (left) in his office at CERN. (Image: Sophia Bennett/CERN).

But we’ll only know whether it’s something worthwhile with the start of the LHC this month, May 2016, when experimental physicists can start to take even more data and conclude what it is.

Next generation of theory

This unusual period of quiet in the world of theoretical physics means students studying physics might be more likely to go into experimental physics, where the major discoveries are seen as happening more often, and where young physicists have a chance to be the first to a discovery.

Speaking to the Summer Students at CERN, some of whom hope to become theoretical physicists, there is the feeling that this period of uncertainty makes following theory a luxury, one that young physicists, who need to have original ideas and publish lots of papers to get ahead, can’t afford.

Image above: Camille Bonvin is working as a fellow in the Theory Department on cosmology to try and understand why the universe is accelerating. If gravity is described by Einstein’s theory of general relativity the expansion should be slowing, not accelerating, which means there’s something we don’t understand. Bonvin is trying to find out what that is. Bonvin thinks the best theories are simple, consistent and make sense, like general relativity. "Einstein is completely logical, and his theory makes sense. Sometimes you have the impression of taking a theory which already exists and adding one element, then another, then another, to try and make the data fit it better, but its not a fundamental theory, so for me its not extremely beautiful." (Image: Sophia Bennett/CERN).

Camille Bonvin, a young theoretical physicist at CERN hopes that the data bump is the key to new physics, because without new discoveries it’s hard to keep a younger generation interested: “If both the LHC and the upcoming cosmological surveys find no new physics, it will be difficult to motivate new theorists. If you don't know where to go or what to look for, it's hard to see in which direction your research should go and which ideas you should explore.”

The future's bright

Richard Feynman, one of the most famous theoretical physicists once joked, "Physics is like sex. Sure, it may give some practical results, but that's not why we do it."

And Gian Giudice agrees –while the field’s current uncertainty makes it more difficult for young people to make breakthroughs, it’s not the promise of glory that encourages people to follow the theory path, but just a simple passion in why our universe is the way it is.

“It must be difficult for the new generations of young researchers to enter theoretical physics now when it is not clear where different directions are leading to,” he says. “But it's much more interesting to play when you don't know what's going to happen, rather than when the rules of the game have already been settled.”

Image above: “It's much more interesting to play when you don't know what's going to happen, rather than when the rules of the game have already been settled,” says Giudice, who took on the role of leading the department in 2016 (Image: Sophia Bennett/ CERN) (Image: Sophia Bennett/CERN).

Giudice, who took on the role of leading the theory department in January 2016 is optimistic that the turbulence the field currently faces makes it one of the most exciting times to become a theoretical physicist.

“It has often been said that it is difficult to make predictions; especially about the future. It couldn't be more true today in particle physics. This is what makes the present so exciting. Looking back in the history of physics you'll see that moments of crisis and confusion were invariably followed by great revolutionary ideas. I hope it's about to happen again,” smiles Giudice.

The next article in the “In Theory” series will discuss the theorists' hopes for the future and what the next steps are for the discipline. You can read the previous articles in the series here:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

This NASA/ESA Hubble Space Telescope image shows star clusters encircling a galaxy, like bees buzzing around a hive. The hive in question is an edge-on lenticular galaxy NGC 5308, located just under 100 million light-years away in the constellation of Ursa Major (The Great Bear).

Members of a galaxy type that lies somewhere between an elliptical and a spiral galaxy, lenticular galaxies such as NGC 5308 are disk galaxies that have used up, or lost, the majority of their gas and dust. As a result, they experience very little ongoing star formation and consist mainly of old and aging stars. On Oct. 9, 1996, scientists saw one of NGC 5308’s aging stars meet dramatic demise, exploding as a spectacular Type la supernova.

Lenticular galaxies are often orbited by gravitationally bound collections of hundreds of thousands of older stars. Called globular clusters, these dense collections of stars form a delicate halo as they orbit around the main body of NGC 5308, appearing as bright dots on the dark sky.

The dim, irregular galaxy to the right of NGC 5308 is known as SDSS J134646.18+605911.9.

Why has the sea ice cover surrounding Antarctica been increasing slightly, in sharp contrast to the drastic loss of sea ice occurring in the Arctic Ocean? A new NASA-led study finds the geology of Antarctica and the Southern Ocean are responsible.

A NASA/NOAA/university team led by Son Nghiem of NASA's Jet Propulsion Laboratory, Pasadena, California, used satellite radar, sea surface temperature, land form and bathymetry (ocean depth) data to study the physical processes and properties affecting Antarctic sea ice. They found that two persistent geological factors -- the topography of Antarctica and the depth of the ocean surrounding it -- are influencing winds and ocean currents, respectively, to drive the formation and evolution of Antarctica's sea ice cover and help sustain it.

Image above: Location of the southern Antarctic Circumpolar Current front (white contour), with -1 degree Celsius sea surface temperature lines (black contours) on Sept. 22 each year from 2002-2009, plotted against a chart of the depth of the Southern Ocean around Antarctica. The white cross is Bouvet Island. Image Credits: NASA/JPL-Caltech.

"Our study provides strong evidence that the behavior of Antarctic sea ice is entirely consistent with the geophysical characteristics found in the southern polar region, which differ sharply from those present in the Arctic," said Nghiem.

Antarctic sea ice cover is dominated by first-year (seasonal) sea ice. Each year, the sea ice reaches its maximum extent around the frozen continent in September and retreats to about 17 percent of that extent in February. Since the late 1970s, its extent has been relatively stable, increasing just slightly; however, regional differences are observed.

Over the years, scientists have floated various hypotheses to explain the behavior of Antarctic sea ice, particularly in light of observed global temperature increases. Are changes in the ozone hole involved? Could fresh meltwater from Antarctic ice shelves be making the ocean surface less salty and more conducive to ice formation, since salt inhibits freezing? Are increases in the strength of Antarctic winds causing the ice to thicken? Something is protecting Antarctic sea ice, but a definitive answer has remained elusive.

To tackle this cryospheric conundrum, Nghiem and his team adopted a novel approach. They analyzed radar data from NASA's QuikScat satellite from 1999 to 2009 to trace the paths of Antarctic sea ice movements and map its different types. They focused on the 2008 growth season, a year of exceptional seasonal variability in Antarctic sea ice coverage.

Their analyses revealed that as sea ice forms and builds up early in the sea ice growth season, it gets pushed offshore and northward by winds, forming a protective shield of older, thicker ice that circulates around the continent. The persistent winds, which flow downslope off the continent and are shaped by Antarctica's topography, pile ice up against the massive ice shield, enhancing its thickness. This band of ice, which varies in width from roughly 62 to 620 miles (100 to 1,000 kilometers), encapsulates and protects younger, thinner ice in the ice pack behind it from being reduced by winds and waves.

The team also used QuikScat radar data to classify the different types of Antarctic sea ice. Older, thicker sea ice returns a stronger radar signal than younger, thinner ice does. They found the sea ice within the protective shield was older and rougher (due to longer exposure to wind and waves), and thicker (due to more ice growth and snow accumulation). As the sea ice cover expands and ice drifts away from the continent, areas of open water form behind it on the sea surface, creating "ice factories" conducive to rapid sea ice growth.

To address the question of how the Southern Ocean maintains this great sea ice shield, the team combined sea surface temperature data from multiple satellites with a recently available bathymetric chart of the depth of the world's oceans. Sea surface temperature data reveal that at the peak of ice growth season, the boundary of the ice shield remains behind a 30-degree Fahrenheit (-1 degree Celsius) temperature line surrounding Antarctica. This temperature line corresponds with the southern Antarctic Circumpolar Current front, a boundary that separates the circulation of cold and warm waters around Antarctica. The team theorized that the location of this front follows the underwater bathymetry.

When they plotted the bathymetric data against the ocean temperatures, the pieces fit together like a jigsaw puzzle. Pronounced seafloor features strongly guide the ocean current and correspond closely with observed regional Antarctic sea ice patterns. For example, the current stays near Bouvet Island, located 1,000 miles (1,600 kilometers) from the nearest land, where three tectonic plates join to form seafloor ridges. Off the coast of East Antarctica, the -1 degree Celsius sea surface temperature lines closely bundle together as they cross the Kerguelen Plateau (a submerged microcontinent that broke out of the ancient Gondwana supercontinent), through a deep channel called the Fawn Trough. But those lines spread apart over adjacent deep ocean basins, where seafloor features are not pronounced. Off the West Antarctica coast, the deep, smooth seafloor loses its grip over the current, allowing sea ice extent to decrease and resulting in large year-to-year variations.

Study results are published in the journal Remote Sensing of Environment. Other participating institutions include the Joint Institute for Regional Earth System Science and Engineering at UCLA; the Applied Physics Laboratory at the University of Washington in Seattle; and the U.S. National/Naval Ice Center, NOAA Satellite Operations Facility in Suitland, Maryland. Additional funding was provided by the National Science Foundation.

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

The Sentinel-1A radar satellite has detected a potential oil slick in the eastern Mediterranean Sea – in the same area where EgyptAir flight MS804 disappeared early yesterday morning on its way from Paris to Cairo.

The image was acquired by Sentinel-1A yesterday at 16:00 GMT (18:00 CEST).

Sentinel-1A detects slick

ESA has given information related to the image to the relevant authorities to support the search operations.

Since the plane disappeared, ESA and experts have been scrutinising satellite data to see if anything could be found to indicate wreckage or oil floating on the sea.

According to the satellite image, the slick was at 33°32' N / 29°13' E – about 40 km southeast of the last known location of the aircraft. The slick is about 2 km long.

There is, however, no guarantee that the slick is from the missing aircraft.

A second image from this morning at 04:00 GMT (06:00 CEST) shows that the slick has drifted by about 5 km.

Closer view of slick

The Sentinel-2A satellite will pass above the same area on 22 May, and experts will continue to study the images returned for further clues.

Both Sentinel satellites were launched as part of Europe’s environmental monitoring Copernicus programme, led by the European Commission.

Sentinel-1A satellite

ESA and the European Commission have released this information in parallel.

André Borschberg will takeoff for the third leg of the crossing of the USA with Si2 from Tulsa International Airport to Dayton International Airport on May 21st at 9:00 AM UTC, 11:00 AM CET, 4:00 AM CDT.

Solar Impulse 2 (Si2)

After one week in stormy Tulsa, Oklahoma, the mission engineers in Monaco have found a clear flight path giving way for an 18 hour flight to reach the very city where the Wright Brothers completed the first controlled, sustained flight of a powered aircraft. The objective is still to reach New York as soon as possible!

jeudi 19 mai 2016

The final set of Cubesats was ejected from the International Space Station today. Inside the orbital lab, the station residents continued more rodent bone and muscle research, checked for microbes and cleaned fans.

A total of 17 Cubesats have been released since Monday from a small satellite deployer on the outside of the Kibo experiment module’s airlock. The suite of Cubesats deployed today will provide Earth observations, improve commercial ship tracking and provide weather data on the Earth’s seas.

Image above: A pair of Cubesats is seen moments after being released from a small satellite deployer on the outside of the Kibo experiment module. Image Credit: NASA.

Bone density measurements were on the schedule again for the mice being monitored as part of the Rodent Research-3 study. The experiment is researching the bone and muscle wasting that takes place in space and is exploring an antibody to prevent musculoskeletal weakness to benefit astronauts and people on Earth.

The crew sampled and analyzed the station’s surfaces and air for microbes to monitor and protect the orbital lab’s environment. Ventilation fans in the U.S. Destiny lab module were also inspected and cleaned today to keep the air clean and flowing keeping the environment safe.

In looking over images of Pluto’s informally named Venera Terra region, New Horizons scientists have spotted an expanse of terrain they describe as “fretted.” As shown in the enhanced-color image at top, this terrain consists of bright plains divided into polygon-shaped blocks by a network of dark, connected valleys typically reaching a few miles (3 to 4 kilometers) wide. Numerous impact craters of up to 15 miles (25 kilometers) in diameter also dot the area, implying the surface formed early in Pluto’s history.

New Horizons scientists haven’t seen this type of terrain anywhere else on Pluto; in fact, it’s rare terrain across the solar system – the only other well-known example of such being Noctis Labyrinthus on Mars. The distinct interconnected valley network was likely formed by extensional fracturing of Pluto’s surface. The valleys separating the blocks may then have been widened by movement of nitrogen ice glaciers, or flowing liquids, or possibly by ice sublimation at the block margins. Compositional data from New Horizons’ Ralph/Multispectral Visible Imaging Camera (MVIC), shown in the bottom image, indicate that the blocks are rich in methane ice (shown as false-color purple); methane is susceptible to sublimation at Pluto surface conditions.

The resolution of these MVIC images is approximately 2,230 feet (680 meters) per pixel. They were obtained at a range of approximately 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before New Horizons’ closest approach on July 14, 2015.

Image above: Hubble Space Telescope photo of Mars taken when the planet was 50 million miles from Earth on May 12, 2016. Image Credits: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (ASU), and M. Wolff (Space Science Institute).

Bright, frosty polar caps, and clouds above a vivid, rust-colored landscape reveal Mars as a dynamic seasonal planet in this NASA Hubble Space Telescope view taken on May 12, 2016, when Mars was 50 million miles from Earth. The Hubble image reveals details as small as 20 to 30 miles across.

The large, dark region at far right is Syrtis Major Planitia, one of the first features identified on the surface of the planet by seventeenth-century observers. Christiaan Huygens used this feature to measure the rotation rate of Mars. (A Martian day is about 24 hours and 37 minutes.) Today we know that Syrtis Major is an ancient, inactive shield volcano. Late-afternoon clouds surround its summit in this view.

A large oval feature to the south of Syrtis Major is the bright Hellas Planitia basin. About 1,100 miles across and nearly five miles deep, it was formed about 3.5 billion years ago by an asteroid impact.

The orange area in the center of the image is Arabia Terra, a vast upland region in northern Mars that covers about 2,800 miles. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest terrains on the planet. Dried river canyons (too small to be seen here) wind through the region and empty into the large northern lowlands.

South of Arabia Terra, running east to west along the equator, are the long dark features known as Sinus Sabaeus (to the east) and Sinus Meridiani (to the west). These darker regions are covered by dark bedrock and fine-grained sand deposits ground down from ancient lava flows and other volcanic features. These sand grains are coarser and less reflective than the fine dust that gives the brighter regions of Mars their ruddy appearance. Early Mars watchers first mapped these regions.

An extended blanket of clouds can be seen over the southern polar cap. The icy northern polar cap has receded to a comparatively small size because it is now late summer in the northern hemisphere. Hubble photographed a wispy afternoon lateral cloud extending for at least 1,000 miles at mid-northern latitudes. Early morning clouds and haze extend along the western limb.

Image above: Hubble's new Mars image indicating major features on the face of the planet. Image Credits: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (ASU), and M. Wolff (Space Science Institute).

This hemisphere of Mars contains landing sites for several NASA Mars surface robotic missions, including Viking 1 (1976), Mars Pathfinder (1997), and the still-operating Opportunity Mars rover. The landing sites of the Spirit and Curiosity Mars rovers are on the other side of the planet.

This observation was made just a few days before Mars opposition on May 22, when the sun and Mars will be on exact opposite sides of Earth, and when Mars will be at a distance of 47.4 million miles from Earth. On May 30, Mars will be the closest it has been to Earth in 11 years, at a distance of 46.8 million miles. Mars is especially photogenic during opposition because it can be seen fully illuminated by the sun as viewed from Earth.

The biennial close approaches between Mars and Earth are not all the same. Mars' orbit around the sun is markedly elliptical; the close approaches to Earth can range from 35 million to 63 million miles.

They occur because about every two years Earth's orbit catches up to Mars' orbit, aligning the sun, Earth, and Mars in a straight line, so that Mars and the sun are on "opposing" sides of Earth. This phenomenon is a result of the difference in orbital periods between Earth's orbit and Mars' orbit. While Earth takes the familiar 365 days to travel once around the sun, Mars takes 687 Earth days to make its trip around our star. As a result, Earth makes almost two full orbits in the time it takes Mars to make just one, resulting in the occurrence of Martian oppositions about every 26 months.

Hubble's New View of Mars and Planets

Video above: The Hubble Space Telescope is more well known for its picturesque views of nebulae and galaxies, but it's also useful for studying our own planets, including Mars. Video Credits: NASA/Goddard/Katrina Jackson.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

For images and more information about the Mars observation and Hubble, visit:

New findings based on a year's worth of observations from NASA’s Van Allen Probes have revealed that the ring current – an electrical current carried by energetic ions that encircles our planet – behaves in a much different way than previously understood.

The ring current has long been thought to wax and wane over time, but the new observations show that this is true of only some of the particles, while other particles are present consistently. Using data gathered by the Radiation Belt Storm Probes Ion Composition Experiment, or RBSPICE, on one of the Van Allen Probes, researchers have determined that the high-energy protons in the ring current change in a completely different way from the current’s low-energy protons. Such information can help adjust our understanding and models of the ring current – which is a key part of the space environment around Earth that can affect our satellites.

The findings were published in Geophysical Research Letters.

Images above: uring periods when there are no geomagnetic storms affecting the area around Earth (left image), high-energy protons (with energy of hundreds of thousands of electronvolts, or keV; shown here in orange) carry a substantial electrical current that encircles the planet, also known as the ring current. During periods when geomagnetic storms affect Earth (right), new low-energy protons (with energy of tens of thousands of electronvolts, or keV; shown here in magenta) enter the near-Earth region, enhancing the pre-existing ring current. Images Credits: Johns Hopkins APL.

“We study the ring current because, for one thing, it drives a global system of electrical currents both in space and on Earth’s surface, which during intense geomagnetic storms can cause severe damages to our technological systems," said lead author of the study Matina Gkioulidou, a space physicist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “It also modifies the magnetic field in near-Earth space, which in turn controls the motion of the radiation belt particles that surround our planet. That means that understanding the dynamics of the ring current really matters in helping us understand how radiation belts evolve as well.”

The ring current lies at a distance of approximately 6,200 to 37,000 miles (10,000 to 60,000 km) from Earth. The ring current was hypothesized in the early 20th century to explain observed global decreases in the Earth’s surface magnetic field, which can be measured by ground magnetometers. Such changes of the ground magnetic field are described by what's called the Sym-H index.

“Previously, the state of the ring current had been inferred from the variations of the Sym-H index, but as it turns out, those variations represent the dynamics of only the low-energy protons,” said Gkioulidou. “When we looked at the high-energy proton data from the RBSPICE instrument, however, we saw that they were behaving in a very different way, and the two populations told very different stories about the ring current.”

The Van Allen Probes, launched in 2012, offer scientists the first chance in recent history to continuously monitor the ring current with instruments that can observe ions with an extremely wide range of energies. The RBSPICE instrument has captured detailed data of all types of these energetic ions for several years. “We needed to have an instrument that measures the broad energy range of the particles that carry the ring current, within the ring current itself, for a long period of time,” Gkioulidou said. A period of one year from one of the probes was used for the team’s research.

“After looking at one year of continuous ion data it became clear to us that there is a substantial, persistent ring current around the Earth even during non-storm times, which is carried by high-energy protons. During geomagnetic storms, the enhancement of the ring current is due to new, low-energy protons entering the near-Earth region. So trying to predict the storm-time ring current enhancement while ignoring the substantial pre-existing current is like trying to describe an elephant after seeing only its feet,” Gkioulidou said.

The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, built and operates the Van Allen Probes for NASA's Science Mission Directorate. RBSPICE is operated by the New Jersey Institute of Technology in Newark, New Jersey. The mission is the second mission in NASA's Living With a Star program, managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland.

mercredi 18 mai 2016

Imagine you’re sitting in class watching a scene from “Star Wars” and your professor assigns a project meant to fly in space.

Image above: The three on-orbit SPHERES satellites fly in formation through the International Space Station, appearing like a squadron star fighters from the Star Wars universe. Image Credits: NASA/ISS.

In 1999, that is exactly what happened for engineering students at the Massachusetts Institute of Technology in Cambridge, Massachusetts.

“On the first day of class, I showed the students the clip where Luke Skywalker learns to channel the Force using the free-floating practice droid on the Millennium Falcon spacecraft,” explained David Miller, the professor and creator of the course. “I said that I want three of these droids to fly on the shuttle or International Space Station, except without the lasers blasts," said Miller, now NASA's chief technologist. "And the rest is history.”

Seventeen years later, that class project, called SPHERES -- Synchronized Position Hold, Engage, Reorient, Experimental Satellites -- is celebrating a rare milestone: 10 years of investigation on the International Space Station (ISS).

SPHERES: The Prequel

SPHERES was initially envisioned to be a fleet of space-based satellites to test computer programs for close-formation flying of spacecraft for advanced telescopes, on-orbit satellite servicing and automated docking.

Prior to the first on-orbit test on May 18, 2006, though, Miller realized SPHERES could also host experiments.

Steve Sell, project manager for SPHERES during the early stages of development and operations at Payload Sciences Inc. in Boston, Massachusetts, recalls when Miller approached the small team late in development. “The computer board had a port on it that was available,” Sell said. “Dr. Miller challenged us to figure out a way to get that port out to the outside so we could plug stuff on, and we did.” The project became a research facility for interchangeable experiments onboard the world’s preeminent research laboratory orbiting Earth.

That’s No Satellite! It’s an Experiment Platform!

Image above: Halo -- seen here attached to a blue SPHERES satellite -- is the newest addition to the SPHERES facility. Each Halo attachment is comprised of printed circuit boards, enclosed in 3-D printed plastic, and six expansion ports -- each with power, data connections and computing capabilities. Image Credit: MIT.

These interchangeable add-ons take many forms. A ring-shaped hexagonal structure called SPHERES Halo, resembling a TIE fighter spacecraft in the Star Wars universe, is attached to the satellites enabling them to fly more complicated configurations and host more experiments than before.

Another notable SPHERES-hosted investigation is SPHERES Slosh, a study aimed at understanding the movement of liquid rocket fuels in space.

“Fuels slosh around in the tanks,” said Jose Benavides, program manager for SPHERES at NASA’s Ames Research Center in California’s Silicon Valley. “That slosh adds forces to the direction the rocket is travelling, and if those forces are too big, they’re going to knock the rocket off course, and then bad things happen.”

To simulate the slosh, two SPHERES satellites maneuver a clear container, partially filled with water dyed Yoda-green; a camera and sensors record the liquid’s movement. Researchers incorporate experiment data into computer models, enabling engineers to design safer and more efficient rockets for spaceflight and NASA’s journey to Mars.

Animation above: NASA astronaut Kjell Lindgren and JAXA astronaut Kimiya Yui recorded video of liquids in a small tank as part of the SPHERES Slosh investigation into microgravity fluid dynamics on the International Space Station. Data could help scientists design better fuel systems for future space craft. Animation Credit: NASA.

“For the first time in history, we have validated computer models that allow us to predict the motion of the fluid in the propellant tanks of spacecraft,” Brandon Marsell, principal investigator for SPHERES Slosh. “That’s huge for rocket technology!”

These Are the Droids You’re Looking For…Kind of

In September 2011, the teams added smartphones to the satellites for the project Smart SPHERES, transforming SPHERES into robots capable of performing tasks for astronauts or flight controllers. The tasks are often either too risky or too repetitive and mundane for the crew, freeing the astronauts for activities requiring a human touch.

The project tested ground remote control of the satellites to fly inside the station and provide camera views to the flight controllers as well as testing the robots’ abilities to follow astronauts using facial detection.

When robotic missions rendezvous with tumbling asteroids or satellites, they will need an automated way of navigating around the object. SPHERES VERTIGO develops software for vision-based navigation and characterization of tumbling objects using stereo cameras and a computer attached to each satellite. SPHERES then builds 3-D digital models of the object and can navigate around it solely using the model.

An Astronaut’s Question Leads to a Student Competition in Space

When astronaut Greg Chamitoff returned from the space station, he inquired about SPHERES’ software and learned that anyone could program it without violating safety assurance.

Student teams worldwide develop computer code for a video game based on a specific NASA challenge, solvable with small, SPHERES-like satellites. Simulations narrow the field and ultimately determine the finalists whose code is tested on the actual SPHERES satellites on ISS, facilitated by on-orbit astronauts.

In its eighth year, the competition proves to be a valuable tool for engaging the next generation of scientists, explorers and engineers while teaching about real-world, off-world challenges.

The SPHERES Legacy

Seventeen years ago in a classroom not that far away, the SPHERES facility was born. As it prepares to hand off its lightsaber of experimentation to the next generation robotic free-flyer, Astrobee, in 2018, team members are looking ahead to the future, while celebrating the successes of nearly 600 test hours over 114 test sessions by 38 on-orbit crew members.

Like SPHERES, Astrobee will be used as a research facility and a remotely-operated robot that can be supervised by mission control for mobile camera work, environment sensing and automated logistics.

Space Station Live: Getting the Buzz on Astrobee

Video Credits: NASA/JSC.

NASA Ames will operate and maintain Astrobee, just as it currently does with SPHERES. Astrobee is funded by the Game Changing Development Program -- part of the NASA’s Space Technology Mission Directorate -- and the Human Exploration and Operations Mission Directorate, both at NASA Headquarters in Washington. Similarly, SPHERES is also funded by the Human Exploration and Operations Mission Directorate.

Perhaps the biggest takeaway from the multi-colored, bowling ball-sized SPHERES satellites is not in the data returned or the similarities to Astrobee but in the classroom where it all began. “Just because something is a student project doesn’t mean it’s only academic,” said Sell. “You can take a student project and turn it into something really great. That’s just a wonderful thing.”

In this image from ESO’s Very Large Telescope (VLT), light from blazing blue stars energises the gas left over from the stars’ recent formation. The result is a strikingly colourful emission nebula, called LHA 120-N55, in which the stars are adorned with a mantle of glowing gas. Astronomers study these beautiful displays to learn about the conditions in places where new stars develop.

LHA 120-N55, or N55 as it is usually known, is a glowing gas cloud in the Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way located about 163 000 light-years away. N55 is situated inside a supergiant shell, or superbubble called LMC 4. Superbubbles, often hundreds of light-years across, are formed when the fierce winds from newly formed stars and shockwaves from supernova explosions work in tandem to blow away most of the gas and dust that originally surrounded them and create huge bubble-shaped cavities.

LHA 120-N55 in the constellation of Dorado

The material that became N55, however, managed to survive as a small remnant pocket of gas and dust. It is now a standalone nebula inside the superbubble and a grouping of brilliant blue and white stars — known as LH 72 — also managed to form hundreds of millions of years after the events that originally blew up the superbubble. The LH 72 stars are only a few million years old, so they did not play a role in emptying the space around N55. The stars instead represent a second round of stellar birth in the region.

The recent rise of a new population of stars also explains the evocative colours surrounding the stars in this image. The intense light from the powerful, blue–white stars is stripping nearby hydrogen atoms in N55 of their electrons, causing the gas to glow in a characteristic pinkish colour in visible light. Astronomers recognise this telltale signature of glowing hydrogen gas throughout galaxies as a hallmark of fresh star birth.

Zooming in on the glowing gas cloud LHA 120-N55 in the Large Magellanic Cloud

While things seem quiet in the star-forming region of N55 for now, major changes lie ahead. Several million years hence, some of the massive and brilliant stars in the LH 72 association will themselves go supernova, scattering N55’s contents. In effect, a bubble will be blown within a superbubble, and the cycle of starry ends and beginnings will carry on in this close neighbour of our home galaxy.

This new image was acquired using the FOcal Reducer and low dispersion Spectrograph (FORS2) instrument attached to ESO's VLT. It was taken as part of the ESO Cosmic Gems programme, an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

Close-up view of the glowing gas cloud LHA 120-N55 in the Large Magellanic Cloud

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ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

mardi 17 mai 2016

Warming up for a possible extended mission as it speeds through deep space, NASA’s New Horizons spacecraft has now twice observed 1994 JR1, a 90-mile-wide (145-kilometer-wide) Kuiper Belt object (KBO) orbiting more than 3 billion miles (5 billion kilometers) from the sun. Science team members have used these observations to reveal new facts about this distant remnant of the early solar system.

Taken with the spacecraft’s Long Range Reconnaissance Imager (LORRI) on April 7-8 from a distance of about 69 million miles (111 million kilometers), the images shatter New Horizons’ own record for the closest-ever views of this KBO in November 2015, when New Horizons detected JR1 from 170 million miles (280 million kilometers) away.

Animation above, the first two of the 20 observations that New Horizons made of 1994 JR1 in April 2016. The Kuiper Belt object is the bright moving dot indicated by the arrow. The dots that do not move are background stars. The moving feature in the top left is an internal camera reflection (a kind of selfie) caused by illumination by a very bright star just outside of LORRI's field of view; it shows the three arms that hold up LORRI's secondary mirror. Animation Credits: NASA/JHUAPL/SwRI.

Simon Porter, a New Horizons science team member from Southwest Research Institute (SwRI) in Boulder, Colorado, said the observations contain several valuable findings. “Combining the November 2015 and April 2016 observations allows us to pinpoint the location of JR1 to within 1,000 kilometers (about 600 miles), far better than any small KBO,” he said, adding that the more accurate orbit also allows the science team to dispel a theory, suggested several years ago, that JR1 is a quasi-satellite of Pluto.

From the closer vantage point of the April 2016 observations, the team also determined the object’s rotation period, observing the changes in light reflected from JR1’s surface to determine that it rotates once every 5.4 hours (or a JR1 day). “That’s relatively fast for a KBO,” said science team member John Spencer, also from SwRI. “This is all part of the excitement of exploring new places and seeing things never seen before.”

Graphic above: New Horizons scientists used light curve data – the variations in the brightness of light reflected from the object’s surface – to determine JR1’s rotation period of 5.4 hours. Graphic Credits: NASA/JHUAPL/SwRI.

Spencer added that these observations are great practice for possible close-up looks at about 20 more ancient Kuiper Belt objects that may come in the next few years, should NASA approve an extended mission. New Horizons flew through the Pluto system on July 14, 2015, making the first close-up observations of Pluto and its family of five moons. The spacecraft is on course for an ultra-close flyby of another Kuiper Belt object, 2014 MU69, on Jan. 1, 2019.

The four planets of the Kepler-223 star system appeared to have little in common with the planets of our own solar system today. But a new study using data from NASA's Kepler space telescope suggests a possible commonality in the distant past. The Kepler-223 planets orbit their star in the same configuration that Jupiter, Saturn, Uranus and Neptune may have had in the early history of our solar system, before migrating to their current locations.

"Exactly how and where planets form is an outstanding question in planetary science," said the study's lead author, Sean Mills, a graduate student in astronomy and astrophysics at the University of Chicago in Illinois. "Our work essentially tests a model for planet formation for a type of planet we don't have in our solar system."

Image above: Sean Mills (left) and Daniel Fabrycky (right), researchers at the University of Chicago, describe the complex orbital structure of the Kepler-223 system in a new study. Image Credits: Nancy Wong/University of Chicago.

The puffy, gaseous planets orbiting Kepler-223, all of which are far more massive than Earth, orbit close to their star. "That's why there's a big debate about how they formed, how they got there and why don't we have an analogous planet in our solar system," Mills said.

Mills and his collaborators used data from Kepler -- its mission is now known as K2 -- to analyze how the four planets block their stars' light and change each other's orbits. This information also gave researchers the planets' sizes and masses. The team performed numerical simulations of planetary migration that generate this system's current architecture, similar to the migration suspected for the solar system's gas giants. These calculations are described in the May 11 Advance Online edition of Nature.

Orbital evolution in Kepler-223

Video above: These animations show approximately 200,000 years of orbital evolution in the Kepler-223 planetary system. The planets’ interactions with the disk of gas and dust in which they formed caused their orbits to shrink toward their star over time at differing rates.

The orbital configuration of our own solar system seems to have evolved since its birth 4.6 billion years ago. The four known planets of the much older Kepler-223 system, however, have maintained a single orbital configuration for far longer.

Astronomers call the planets of Kepler-223 "sub-Neptunes." They likely consist of a solid core and an envelope of gas, and they orbit their star in periods ranging from only seven to 19 days. They are the most common type of planets known in the galaxy, even though there is nothing quite like them around our sun.

Kepler-223's planets also are in resonance, meaning their gravitational influence on each other creates a periodic relationship between their orbits. Planets are in resonance when, for example, every time one of them orbits its sun once, the next one goes around twice. Three of Jupiter's largest moons, where the phenomenon was discovered, display resonances. Kepler-223 is the first time that four planets in an extrasolar system have been confirmed to be in resonance.

"This is the most extreme example of this phenomenon," said study co-author Daniel Fabrycky, an assistant professor of astronomy and astrophysics at the University of Chicago.

Formation scenarios

The Kepler-223 system provides alternative scenarios for how planets form and migrate in a planetary system that is different from our own, said study co-author Howard Isaacson, a research astronomer at the University of California, Berkeley, and member of the California Planet Search Team.

"Data from Kepler and the Keck Telescope were absolutely critical in this regard," Isaacson said. Thanks to observations of Kepler-223 and other exoplanetary systems, "We now know of systems that are unlike our sun's solar system, with hot Jupiters, planets closer than Mercury or in between the size of Earth and Neptune, none of which we see in our solar system. Other types of planets are very common."

Some stages of planet formation can involve violent processes. But during other stages, planets can evolve from gaseous disks in a smooth, gentle way, which is probably what the sub-Neptune planets of Kepler-223 did, Mills said.

Kepler Space Telescope. Image Credit: NASA

"We think that two planets migrate through this disk, get stuck and then keep migrating together; find a third planet, get stuck, migrate together; find a fourth planet and get stuck," Mills explained.

That process differs completely from the one that scientists believe led to the formation of Mercury, Venus, Earth and Mars, which likely formed in their current orbital locations.

Earth formed from Mars-sized or moon-sized bodies smacking together, Mills said, in a violent and chaotic process. When planets form this way, their final orbital periods are not near a resonance.

Substantial movement

But scientists suspect that the solar system's larger, more distant planets of today -- Jupiter, Saturn, Uranus and Neptune -- moved around substantially during their formation. They may have been knocked out of resonances that once resembled those of Kepler-223, possibly after interacting with numerous asteroids and small planets (planetesimals).

"These resonances are extremely fragile," Fabrycky said. "If bodies were flying around and hitting each other, then they would have dislodged the planets from the resonance." But Kepler-223's planets somehow managed to dodge this scattering of cosmic bodies.

NASA's Ames Research Center in Moffett Field, California, manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.